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Remark on the Mean Energy of the Fluctuating Magnetic Field in Mean‐field Magnetohydrodynamics
Author(s) -
Bräuer H.,
Krause F.
Publication year - 1972
Publication title -
astronomische nachrichten
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.394
H-Index - 63
eISSN - 1521-3994
pISSN - 0004-6337
DOI - 10.1002/asna.19722940406
Subject(s) - physics , isotropy , magnetic field , magnetohydrodynamics , mean square , mean field theory , square (algebra) , homogeneous , turbulence , field (mathematics) , space (punctuation) , mathematical physics , quantum electrodynamics , condensed matter physics , statistical physics , mathematical analysis , mathematics , quantum mechanics , mechanics , geometry , pure mathematics , linguistics , philosophy
Abstract A relation between the mean square of the fluctuating magnetic field, B′ , and the square of the mean magnetic field, B̄ , is derived for the case of homogeneous isotropic turbulence. The second order correlations approximation is used under the assumption that the space and time scales L̄ and T̄ of the mean field are large compared with the scales L and T of the fluctuations. B OCHNER 's theorem manifests itself as a guarantee for the ratio B̄′ 2 |B̄ 2 to be non‐negative.